1. Field of the Invention
The present invention relates to an elevator door apparatus comprising an engaging device that engages a car door with a hall door.
2. Description of the Related Art
An elevator hall in a building is provided with an entrance to a car of an elevator. Hall doors, which are of sliding type, are attached to the entrance. The hall door is normally closed. When the car, moving through an elevator shaft, reaches a floor of the elevator hall, the hall door is opened and closed under the driving force of a car door of the car. The hall door also comprises a lock mechanism. The lock mechanism locks the hall door when it is closed. The lock mechanism unlocks the hall door when an operation of opening the hall door is started.
The car door comprises an engaging device used to open and close the hall door and to operate the lock mechanism. The engaging device comprises a pair of engaging vanes extending in a vertical direction. The engaging vanes vary the distance between themselves in accordance with the operation of the car door, while remaining parallel using parallel links.
The lock mechanism comprises two engaging rollers as engaging members used to operate a lock lever that locks the hall door. The two engaging rollers are interposed between the engaging vanes. The pair of engaging vanes sandwiches the engaging rollers between themselves to engage the car door with the hall door. As a result, the hall door can move in unison with the car door. Further, when the sandwiching of the engaging rollers between the engaging vanes is released, the lock lever is activated to lock the hall door.
When the hall door is closed to complete the activation of the lock mechanism of the hall door, the distance between the pair of engaging vanes increases up to a maximum value. As the result a gap is created between the engaging rollers and each engaging vane. Consequently, the car can move through the elevator shaft while preventing the engaging vanes from colliding against the engaging rollers.
Various engaging apparatus have already been proposed. For example, an engaging apparatus comprises a pair of engaging vanes, a cam roller, and a cam plate. The pair of engaging vanes constitutes a parallelogrammic link. The cam roller is attached to one of the engaging vanes. The cam plate is provided above the car door. The cam roller is guided to the cam plate as the car door is closed. When the cam roller moves up or down along the cam plate immediately before the hall door is closed, the distance between the pair of engaging vanes changes. As a result, the lock mechanism is activated or the car door and the hall door are disengaged from each other.
In an engaging device in another form, one of the pair of engaging vanes is fixed to the car door. Only the other engaging vane constitutes a parallelogrammic link mechanism. A cam roller is attached to the latter engaging vane. The cam roller is guided along a cam plate provided above the car door. The cam roller activates the lock mechanism and releases the engagement immediately before the car door is closed as described above.
To allow the car to move while the doors are completely closed, it is necessary to disengage the doors from each other. With an engaging device comprising a cam mechanism composed of a cam roller and a cam plate as described above, immediately before the door is closed, a gap is created between each engaging vane and the corresponding engaging roller. This blocks the transmission of the driving force from the engaging vane to the engaging roller. The hall door is operated under the force of a door closer that utilizes a weight or a spring from immediately before the door starts to be closed until it is completely closed.
There is an engaging device that disengages the car door and the hall door from each other without using a cam mechanism such as the one described above. This device comprises two support levers connected to the engaging vanes to constitute a parallelogrammic link mechanism. One of the support levers is supported so as to be rotatable around a pivot fixed to the car door. The pivot is connected to a door driving rope via an operation lever. The rope is pulled even after the hall door has been closed. The traction force of the rope is transmitted to a separately provided parallelogrammic link mechanism. The lock mechanism is thus activated to disengage the car door and the hall door from each other.
Another device does not use any cam mechanism. In this device, one of the engaging vanes can slide to and from the car door. The other engaging vane is connected to car door and a car door driving belt by rotatably supported levers. The levers operate to close the hall door. Moreover, even after the car door has been closed, the driving belt continues to be pulled in the direction in which the car door is closed. Thus, even after the car door has been closed, the doors can be disengaged from each other by driving only the engaging vanes. In such a door apparatus, the driving force is transmitted by the rope or belt not only while the door is being closed but also before the hall door is completely closed.
In particular, if there is a difference in temperature between an indoor area and an outdoor area as in the case of winter, a strong ascending current occurs in the elevator shaft of the elevator in a high-rise building. Thus, a large difference in atmospheric pressure occurs between the elevator shaft and the hall. For example, there is no difference in atmospheric pressure at the hall door of an elevator provided near an entrance of the first floor of the building while the door is open.
However, as the door is closed, the flow of air is constricted. Immediately before the door is closed, the difference in pressure between the elevator shaft and the hall increases rapidly. As the wind pressure acting in a direction from the hall to the interior of the elevator shaft increases, a heavier load is imposed on the guide device of the hall door. As a result, there may occur an increase in the frictional resistance of the guide device or in the atmospheric pressure acting on a door stop surface. Consequently, the door may not be completely closed.
In particular, a smoke insulating door that can be more appropriately closed has recently been employed as a hall door also used as a fireproof facility. Accordingly, when the door is closed, the difference in atmospheric pressure increases between the interior of the elevator shaft and the hall. As a result, the tendency to suffer the above disadvantage has become more significant.
With the above door apparatus comprising the cam roller and the cam plate, the force of the door closer can be effectively enhanced in order to deal with the wind pressure. However, the size of a weight or a spring mechanism must be increased in order to enhance the driving force of the door closer. This affects a space in which the elevator is installed. Further, when the driving force of the door closer is enhanced, the driving force of the car door apparatus must also be increased. Consequently, the size of a driving device must be increased. Since a high-rise building comprises a plurality of elevators, it is economically disadvantageous to take the above measure for each of a large number of hall doors installed on each floor.
Further, the latter of the previously described door apparatuses has a very complicated mechanism and is thus difficult to regulate. Accordingly, this apparatus is also economically disadvantageous. Moreover, in this door apparatus, the positions of the car door and the driving rope or belt do not coincide with each other but vary relatively. Thus, if this door apparatus is applied to a center open door, it is necessary to have a mechanism used to operate a right and left doors in unison, in addition to the rope and belt. Disadvantageously, this further complicates the mechanism of the apparatus.